The growth of the automobile industry is indicated by the development of an excellent engine, which can be called the heart of a vehicle, as the clearest evidence. Of course, various factors, such as an increase in fuel consumption ratio, and the prevention of environmental pollution, are taken into account, but the most important factor is a method of allowing a vehicle equipped with an excellent engine to travel at high speed for a long period of time in various environments. The vehicle travel speed increases with the development of the engine, and, consequently, consumers require that safe vehicles be provided.
A large number of vehicle safety systems are developed due to structural factors, such as the requirement to provide airbags, the requirement to wear safety belts, and increased roof strength, and the utilization of auxiliary devices for protecting human life when a collision occurs. In addition to a safety device directly related to a collision, various safety devices, such as a rotating headlight, a reflective mirror for preventing glare from occurring during night driving, and a night fluoroscope using an infrared camera, are introduced.
One factor to which drivers must always pay attention while driving is to check a blind spot. Generally, approaching vehicles are monitored using mirrors, but it is impossible to monitor approaching vehicles present in a blind spot using the mirror when a driver changes lanes or turns a vehicle. In order to prevent accidents from occurring due to the impossibility of checking a blind spot, an auxiliary mirror may be installed, or alternatively, a driver turns his or her head to check, but the driver's gaze is diverted away from the traveling direction, and thus it is difficult to absolutely guarantee the driver's safety. Even a skillful driver may occasionally and instantaneously feel at risk because he or she cannot sense a vehicle in a blind spot when driving in conditions in which the driver's field of vision is poor, such as night driving or driving in environmental conditions such as mist, rain or snow. In particular, recently produced vehicles are equipped with excellent soundproof facilities, and thus there are many cases where approaching vehicles cannot be sensed merely from the noise level sensed inside the vehicles.
According to traffic accident statistics from the road traffic safety authority, about 5.7% of all multiple-vehicle traffic accidents are caused by passing or lane changes. The statistical data shows that, among all accidents, front collision accidents have the highest lethality (10.7 persons/100 cases), and accidents attributable to the impossibility of detecting risks present in rear left/right blind spots have the next highest lethality (6.8 persons/100 cases). Meanwhile, conventional side rear view mirrors have been used as one of the most basic parts of vehicles in the past 70 years from the standpoint of the security of side rear views of vehicles.
FIG. 1 is a diagram showing a region that can be checked by a driver using a conventional side rear view mirror and a blind spot region occurring due to the visual restrictions imposed on a side rear view mirror or a driver.
Referring to FIG. 1, the conventional side rear view mirror has a blind spot (A) having a certain area due to the restriction of the size and angle of the mirror. Generally, the blind spot (A) begins at an angle of 15° with respect to the side of a vehicle body and ends at an angle of 45°. The term “blind spot (A)” means regions that cannot be seen by side rear view mirrors or a rear view mirror fixedly installed to the vehicle, and that correspond to the lower regions of areas in front of and behind the vehicle and regions adjacent to both sides of the vehicle. As the size of a vehicle body increases, the area of the blind spot is increased. Accordingly, as the number of luxury vehicles increases, the number of traffic accidents gradually increases due to the incomplete fields of vision. In order to solve this problem, vehicle blind spot detection technology for preventing accidents by securing as wide a field of vision as possible for a driver has recently been successively developed.
For example, there are technologies, such as technology using mirrors of combining auxiliary mirrors, such as convex mirrors, with the side rear view mirrors of a vehicle and installing the auxiliary mirrors at required locations, screen display (Closed Circuit Television: CCTV)-related technology for reducing the blind spot of a rear view, occurring due to a lane change, by adjusting the angle of a camera and the screen division of a monitor so that the region of a vehicle access road can be seen in detail according to the operation of a turn signal lamp or the like, and technology for generating a warning sound or displaying a warning icon using ultrasonic or laser distance sensors when a person or an obstacle approaches.
Further, since the incidence of traffic accidents attributable to a blind spot during a lane change is high, vehicle manufacturers are taking a great interest in a Blind Spot Detection system (BSD) for preventing traffic accidents. A technique for determining the presence of an obstacle using triangulation, which uses a single emitter and two detectors, that is, a positive detector (PD+) and a negative detector (PD−), was proposed in U.S. Pat. No. 5,418,359, filed in November 1993. U.S. Pat. No. 5,675,326, filed in July 1995, and U.S. Pat. No. 5,463,384, filed in May 1994 (by Auto-Sense Ltd.), disclose a method of configuring an infrared blind slot detector array composed of a plurality of detectors, a method of optically designing respective emitters and detectors, an experimental method of performing vehicle detection using the methods, and the results thereof.
FIG. 2 is a diagram showing the construction of a conventional blind spot detection system, and FIG. 3 is a flowchart showing a process for detecting an obstacle in a blind spot using the conventional blind spot detection system.
As shown in FIGS. 2 and 3, the conventional blind spot detection system includes a turn signal lamp detection means 1 for detecting the operation of a turn signal lamp, an infrared sensor means 2 for detecting an obstacle present in the blind spot of a vehicle, a warning means 3 provided to warn a driver of the possibility of a collision between an obstacle and the driver's vehicle, and a control means 4 for determining whether the turn signal lamp is turned on and automatically driving the warning means 3 when an obstacle is detected in a blind spot present on the side on which the turn signal lamp is turned on.
The conventional blind spot detection system having the above construction is configured such that the infrared sensor means 2, corresponding to a target direction, is operated (S102) by turning on a turn signal lamp (S101), the presence of an obstacle in a blind spot is determined (S103) by the control means 4, and the obstacle is recognized (S104), and such that information about the results of recognition are provided (S105) to the driver through the warning means 3 in the form of a visual and audible warning.
However, in the above operation mechanism, when the driver does not turn on a turn signal lamp, the warning means 3 is not operated even if the driver changes lanes, and does not provide a warning even when a warning must be provided for side impacts.
Therefore, even if an obstacle is detected in a blind spot, which cannot be sensed by a driver at the time of changing lanes, there is no method of informing the driver of the presence of the obstacle, so that the accident prevention function is deteriorated, and the original purpose of the blind spot detection system itself, to decrease the danger of accidents, is defeated.